Drains for household sinks often become clogged by a combination of fatty substances, protein or cellulose fibers and soap. Although soap is a good detergent, it has the disadvantage that it reacts with divalent metallic ions in water such as calcium and magnesium, to form an insoluble curd. This curd, together with small amounts of fatty substances such as oil, grease, fatty substances from the body, cooking oils or even hair grooming products, tends to adhere to the inside of the drain and forms a restriction to the free flow of water. In addition, solid, water insoluble products such as hair, lint or paper may become lodged in the drain at the point of restriction so that a relatively immovable plug is eventually formed in the drain.
Most conventional drain cleaners are composed of concentrated solutions of strong acids such as sulfuric acids or of bases such as sodium hydroxide or combinations of strong oxidizing agents with strong bases. Cleaners of this kind attack the clogging material lodged in the drain at the restriction and are generally effective in removing the plug but they have the disadvantage that they are extremely dangerous materials, especially for household use. Each year, a considerable number of accidents occur with drain cleaners of this kind, either from the cleaner being splashed onto the skin or by small children ingesting inadequately guarded quantities of the cleaner. It would therefore be desirable to develop a relatively less toxic cleaner which would still be effective for removing the blockages in most household drains.
Various combinations of chemical ingredients have been proposed for drain cleaners, with different objectives. For example, U.S. Pat. No. 3,965,048 discloses a drain cleaner composition which is stated to be effective in dissolving soap curd and which contains salts of certain polyamine polycarboxylic acids together with other ingredients such as surfactants, and ingredients such as urea and thyoglycolate salts which are effective in dissolving hair and other water insoluble objects. U.S. Pat. No. 4,206,607 also discloses drain cleaner compositions which are effective in dissolving soap curd and which, besides containing salts of certain amino acids and anionic surfactants, may also contain corrosion inhibitors such as thioglycolate salts and materials such as urea which are capable of promoting the dissolution of hair and other insoluble materials. U.S. Pat. No. 4,206,068 discloses drain cleaner compositions which are based on a redox system together with a relatively large amount of a caustic alkali such as sodium hydroxide. Upon use in the drain, the redox system develops a substantial amount of heat upon dissolving in the standing water in the drain and this assists dissolution of hair and fatty substances making up the plug. U.S. Pat. No. 2,997,444 discloses a drain cleaning composition based on caustic alkali and an anticlogging agent such as sodium sulfide or sodium thioglycolate.
We have now developed improved drain cleaner compositions which are relatively less toxic than the drain cleaners which are presently commercially available and yet which are still effective in unplugging drains clogged with soap, grease and hair or other insoluble materials.